I think the challenge is the NHC is trying to average the model outputs instead of picking one group. Assume it's 12:30 pm but you don't know this. You ask 4 people to estimate what time it is - 2 tell you it's noon, 2 tell you it's midnight, and not knowing who is right, you decide to go with the average and estimate its 6 pm. You will still be way off. Same principle here - one group of models says it's going to dissipate, one group says it's going to intensify possibly to a CAT 1 hurricane and go north. Clearly one group is really on target and one is way off. But instead of choosing a group they are blending the solutions and coming up with an answer that is bound to be wrong, just less wrong than they would be if they chose one group of model outputs.

This is always the case, and while it may be more of a weakness with Erika than usual, in fairness to the NHC, the expert models are also expertly weighted, and when the forecast isn't verifying well with the expertly weighted averages, we still have expert humans at the helm to make other adjustments as needed.

The science is simply not good enough yet to always handle how these weaker, less organized systems interact with the islands. And this season is already a challenging one to forecast in.

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The NHC never likes to make drastic swings in the forecast track unless absolutely forced to. But Erika's stubbornness on continuing west has created a bit of a forecast issue. They even mention that the models have consistently been wrong about it turning to the northwest. So much so the system has been outside of the cone of uncertainty (for the next point) since Wednesday

So at what point do they go with what they are observing and not what computers are telling them might (could or should) be happening out there since that predicted situation has failed to verify for 2 days now? The good news is Erika continues to take a path that prevents her from strengthening (over mountains, over land, thru shear), so at some point soon we will talking about a depression. Or worst case a small TS that will have very little time over before reaching FL. Unless this west trend continues to the point where she blows by Cuba and enters the GOM.

Hmm the NHC's 8PM Track Graphic is bad, looks like prior coordinates. The misprinted the longitude in the advisory, (and it broke our automated system, so I'm sure it may have broken theirs.) I had to manually edit the coordinates on the left

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Nice catch. It looked more and more like an open wave to me, even with the convective bloom. This clearly shows a mid or low level circulation.

Those microwave images tend to pick up the mid levels, so mid level circulation. It's not a "sudden eye", more just curiously shaped at the moment. However, it means Erika hasn't completely fallen apart, which means it has a shot at strengthening if it does clear the islands. If it were actually like that at the surface, I'd be very shocked.

The other interesting bit, looking at older images from that, it seems to be on the WNW/NW path now (at least at the mid levels) If that holds a few more hours, it may clip just the extreme eastern part of Cuba, and make tomorrow a lot more critical.

The officially tracked LLC does not appear to be all that dislocated from the incipient/potential mid-level circulation seen in the CIMSS loop above. Microwave and DvorakLLC fixing also suggests that it is, at least briefly, also pulling northwest across Haiti in tandem with this mid-level feature.

The 11PM Advisory is out that included useful data from sondes dropped by the P3 flying around Hispaniola tonight. With this additional information, the NHC has been able to place the LLC close to 18.5N 72.9W, which continues the most recent wnw to nw heading.

Glad we have that radar loop. We might of had a nice blow up this evening...but will it have a LLC by 8am this morning. Will it shoot out west and be south of Cuba near 19N and 75.5W or will it follow the WNW to NW path and be in NE Cuba or just offshore...near say 20.5N and 74.5W. It would be nice to still have a LLC to follow but also might just be a open wave with no more W or NW winds

The 5AM center of Erika is suspect, looking at the overall structure a lot of energy is being ejected to the southwest, and a circulation is visible north of the eastern edge of Cuba.

Recon is out there investigating the potential new center right now. If this does become the new center, tracks will shift right again, and Erika has a shot at maintaining or strengthening slightly. If the official center south of Cuba sticks, it is much less likely.

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